Structural highlights
Function
[HDOX2_STAAM] Allows bacterial pathogens to use the host heme as an iron source. Catalyzes the oxidative degradation of the heme macrocyclic porphyrin ring to the oxo-bilirubin chromophore staphylobilin (a mixture of the linear tetrapyrroles 5-oxo-delta-bilirubin and 15-oxo-beta-bilirubin) in the presence of a suitable electron donor such as ascorbate or NADPH--cytochrome P450 reductase, with subsequent release of free iron.[HAMAP-Rule:MF_01272]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Heme-degrading enzymes are involved in human diseases ranging from stroke, cancer, and multiple sclerosis to infectious diseases such as malaria, diphtheria, and meningitis. All mammalian and microbial enzymes identified to date are members of the heme oxygenase superfamily and assume similar monomeric structures with an all alpha-helical fold. Here we describe the crystal structures of IsdG and IsdI, two heme-degrading enzymes from Staphylococcus aureus. The structures of both enzymes resemble the ferredoxin-like fold and form a beta-barrel at the dimer interface. Two large pockets found on the outside of the barrel contain the putative active sites. Sequence homologs of IsdG and IsdI were identified in multiple Gram-positive pathogens. Substitution of conserved IsdG amino acid residues either reduced or abolished heme degradation, suggesting a common catalytic mechanism. This mechanism of IsdG-mediated heme degradation may be similar to that of the structurally related monooxygenases, enzymes involved in the synthesis of antibiotics in Streptomyces. Our results imply the evolutionary adaptation of microbial enzymes to unique environments.
Staphylococcus aureus IsdG and IsdI, heme-degrading enzymes with structural similarity to monooxygenases.,Wu R, Skaar EP, Zhang R, Joachimiak G, Gornicki P, Schneewind O, Joachimiak A J Biol Chem. 2005 Jan 28;280(4):2840-6. Epub 2004 Oct 31. PMID:15520015[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Wu R, Skaar EP, Zhang R, Joachimiak G, Gornicki P, Schneewind O, Joachimiak A. Staphylococcus aureus IsdG and IsdI, heme-degrading enzymes with structural similarity to monooxygenases. J Biol Chem. 2005 Jan 28;280(4):2840-6. Epub 2004 Oct 31. PMID:15520015 doi:M409526200
